Braided medical device and manufacturing method thereof

ABSTRACT

An medical implantable occlusion device ( 100 ) is disclosed having a collapsed state and an expanded state and comprising a braiding ( 101 ) of at least one thread, and a distal end ( 102 ) comprised of said braiding. The distal end comprises loops ( 103, 104, 204, 304 ) formed by loop strands ( 105, 106, 206, 306 ) of the at least one thread, wherein, at least in said expanded state, each loop strand has a curved shape and extends away from a centre point ( 117 ) of the distal end, whereby an apex point ( 107, 108, 208, 308 ) of each of the loop strands corresponds to the turning point of the curved shape and to the point of each of the loop strands being arranged closest to the centre point. At least one of the loop strands is displaced from the centre point by a centre distance ( 109, 110, 210, 310 ), and the apex point lie at a distance from a periphery ( 113 ) of the distal end.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/051,027 filed Feb. 23, 2016 entitled Braided Medical Device AndManufacturing Method Thereof, which is a divisional of U.S. patentapplication Ser. No. 13/698,981 filed Jun. 4, 2013 entitled BraidedMedical Device And Manufacturing Method Thereof, which is the U.S.National Phase of and claims priority to International PatentApplication No. PCT/EP2011/058382, International Filing Date May 23,2011, entitled Braided Medical Device And Manufacturing Method Thereof,which claims benefit of European Application No. 10163680.1, filed May23, 2010 entitled Braided Medical Device And Manufacturing MethodTherefore; and U.S. Provisional Application Ser. No. 61/347,466, filedMay 24, 2010 entitled Braided Medical Device And Manufacturing MethodTherefore; all of which are incorporated herein by reference in theirentireties.

FIELD OF THE INVENTION

This invention pertains in general to the field of braided medicaldevices, as well as methods for manufacturing such devices. Moreparticularly the invention relates to braided occlusion devices.

BACKGROUND OF THE INVENTION

Various braided medical devices are used for treating various conditionsin a patient. In certain circumstances, it may be necessary to use suchdevices for occlusion of a patient's lumen, vessel, chamber, channel,hole, or cavity. When delivering or implanting such devices into thepatient's body it is critical that the braided device is sufficientlyflexible for safe delivery by a delivery device such as a catheter to atarget site in the patient. The ease of operation by which the medicaldevice can be delivered is crucial from several aspects such asrequirements to comply with time limits for quick treatment or overallsafe positioning or manoeuvring of the device at the target site.

Issues with some prior art solutions are that the braided devices arenot sufficiently flexible, and/or that a large force is required tomanipulate the device, for example due to too high stiffness of thebraided mesh of the device. This may lead to a difficult delivery of thebraided device through for example a catheter. For braided deviceshaving an expanded and a collapsed shape configuration the large forceneeded to collapse the device from the relaxed expanded state may leadto difficulties to pull the device into for example the delivery sheathof the catheter. Also, due to this force, making these braided deviceless flexible, the friction between the device and the catheter will betoo high in order to easily move and manipulate the device in thecatheter, for both movement to pull and to push the device in thecatheter. Thus, there is a need for a braided device which allows asecure deployment in the patient.

Insufficient flexibility of some braided devices known in the art mayalso make the positioning of the device in the patient's body moredifficult, for example, by the inability for the device to adapt to theunique anatomy of the target site. Further, a stiff device may lead toinjury at the target site, for example to soft tissues in contact withthe device. There is accordingly a need for a braided device whichadjusts for differences in the anatomies between patients. Further aninflexible device may cause embolies, which could be transported toorgans such as the brain and cause blood clots. This appears inparticular to be the case with some devices having ends clampedtogether. In particular it may be an issue to have a distal end having astructure protruding into an arterial (high blood pressure) blood streamleading to vital organs, such as the brain. One issue are protrudingthreaded clamps keeping together a bundle of strands, such as describedin WO99/12478.

WO2008/040555 discloses a braided occlusion device having foldedsections in two or more layers for positioning in an opening. Sectionsat the distal portion of the device are back-bent towards the proximalportion to contact the tissue of the wall having the opening to beoccluded. The folded sections cause the device to exhibit a substantialamount of wires to be deformed when compressing the device, henceincreasing the force necessary to compress the device and thecross-section of the compressed device.

US2005/0283962 discloses a method of manufacturing a device of a tubularbraiding. An issue with tubular braidings as disclosed in US2005/0283962is insufficient stability that may lead to dislocation of the devicefrom the implanted site.

An issue with prior art braided devices is that catheters with too largecross-section are required, as the devices take up large space even whenin the collapsed state. Some regions of the body may thus only bereached with difficulty by such devices requiring large diametercatheters.

A further disadvantage with prior art is that some devices designed tobe flexible may not have the sufficient retention force to withstandexternal forces.

Above disadvantages and issues may have dire consequences for thepatient and the health care system. Patient risk may be increased.

Hence, an improved implant would be advantageous and in particularallowing for increased flexibility, cost-effectiveness, and/or patientsafety would be advantageous. Also, and a method for manufacturing suchmedical implant would be advantageous.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention preferably seek tomitigate, alleviate or eliminate one or more deficiencies, disadvantagesor issues in the art, such as the above-identified, singly or in anycombination by providing a device and a method according to the appendedpatent claims.

Embodiments of the present invention may be well suited for theselective occlusion of a vessel, lumen, channel, hole, cavity, or thelike. Examples, without limitations, are a vessel, lumen, channel, orhole through which blood flows from one vessel to another vessel such asan Atrial Septal Defect (herein after ASD) or a Ventricular SeptalDefect (herein after VSD). Other examples could be an Arterial VenousFistula (AVF), Arterial Venous Malformation (AVM), a Patent ForamenOvale (PFO), Para-Valvular Leak (PVL), or Patent Ductus Arteriosus.

According to a first aspect of the invention a medical implantableocclusion device is provided having a collapsed state and an expandedstate and comprising a braiding of at least one thread, and a distal endcomprised of the braiding. The distal end comprises loops formed by loopstrands of the at least one thread, wherein, at least in the expandedstate, each loop strand has a curved shape and extends away from acentre point of the distal end. An apex point of each of the loopstrands corresponds to the turning point of the curved shape and to thepoint of each of the loop strands being arranged closest to the centrepoint. At least one of the loop strands is displaced from the centrepoint by a centre distance such that the location of the apex point isdifferent from the centre point.

According to a second aspect of the invention a method of manufacturinga medical implantable occlusion device of a braiding of at least onethread is provided. The method comprises forming loops by loop strandsof the at least one thread by an annular braiding tool having a centrepoint. Each loop strand has a curved shape and extends away from thecentre point of the braiding tool. An apex point of each of the loopstrands corresponds to the turning point of the curved shape and to thepoint of each of the loop strands being arranged closest to the centrepoint. At least one of the loop strands is displaced from the centrepoint by a centre distance such that the location of the apex point isdifferent from the centre point.

Further embodiments of the invention are defined in the dependentclaims, wherein features for the second and subsequent aspects of theinvention are as for the first aspect mutatis mutandis.

Some embodiments of the invention provide for a flexible braided medicaldevice that is easy to manipulate in a delivery device and that adapt tovarying anatomical sites in a body of a human or animal.

Some embodiments of the invention also provide for secure attachment ofa braided medical device in a patient's vascular system.

Some embodiments of the invention provide for a compact braided medicaldevice with maintained flexibility.

Some embodiments of the invention provide for a braided medical devicethat can be safely delivered to a treatment site in a patient.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments ofthe invention are capable of will be apparent and elucidated from thefollowing description of embodiments of the present invention, referencebeing made to the accompanying drawings, in which

FIG. 1 is an illustration of a braided implantable occlusion deviceaccording to an embodiment of the invention;

FIG. 2 is an illustration of a braided implantable occlusion deviceaccording to another embodiment of the invention;

FIG. 3 is an illustration of a braided implantable occlusion deviceaccording to another embodiment of the invention;

FIG. 4 is an illustration of a braided implantable occlusion deviceaccording to another embodiment of the invention;

FIGS. 5a-b are illustrations of a braided implantable occlusion deviceaccording to another embodiment of the invention;

FIGS. 6a-b are illustrations of a braided implantable occlusion deviceaccording to another embodiment of the invention;

FIGS. 7a-b are illustrations of a method for manufacturing of a braidedimplantable occlusion device according to an embodiment of theinvention;

FIG. 8 shows the braided implantable occlusion device according to anembodiment of the invention;

FIG. 9 shows a method of manufacturing a medical implantable occlusiondevice according to an embodiment of the invention; and

FIGS. 10a-b are illustrations of prior art devices.

DESCRIPTION OF EMBODIMENTS

Specific embodiments of the invention will now be described withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the invention to those skilled in the art. Theterminology used in the detailed description of the embodimentsillustrated in the accompanying drawings is not intended to be limitingof the invention. In the drawings, like numbers refer to like elements.

The following description focuses on embodiments of the presentinvention applicable to PFO or ASD devices. However, it will beappreciated that the invention is not limited to this application butmay be applied to many other medical implantable devices, including forexample filters, stents, vascular occluders, Left Atrial Appendage (LAA)occluders, aneurysm treatment devices, grafts, etc.

FIG. 1 shows a braided implantable occlusion device 100 according to anembodiment of the invention. The device 100 comprises a mesh or braiding101 of at least one thread. The braiding 101 may be formed from onethread or several. The device 100, or more particularly the braiding101, has a collapsed state and an expanded state. FIG. 1 depicts an endof the device 100, which in this case is a distal end 102. In otherembodiments (not shown) a proximal end of the device 100, or any otherpart of the device 100, may have the same features as the distal end102. Hence any part of the braiding 101 forming the device may have thefeatures described in the following, with the associated advantages. Thedistal end 102 is comprised of the braiding 101.

The braiding 101 may be made of a material suitable for implanting in ahuman or animal body, and suitable for being formed in a heat treatmentprocedure to a desired shape in an expanded state and also in thecollapsed state. For example NiTinol may be used as a material for thedevice 100. However, suitable materials for embodiments of the braidingare various and include shape memory materials, metal, superelasticalloys (such as NiTinol), or polymers, such as degradable polymers.

The distal end 102 comprises loops 103, 104, formed by loop strands 105,106, of the at least one thread. In at least the expanded state eachloop strand 103, 104, has a curved shape and extends away from a centrepoint 117 of the distal end 102. Thus, each of the loop strands 105, 106has an apex point 107, 108, corresponding to the turning point of thecurved shape and to the point of each of the loop strands that areclosest to the centre point 117.

In FIG. 1 the loops 103, 104, are U-shaped but may have other shapes ofthe open curvature, e.g. elliptical, half circular, or W-shaped. Thecurved shape of the loop strands 103, 104 extending away from the centrepoint 117 should be construed as the opening of the U-shaped curvepoints radially outwards from the centre point 117.

At least one of the loop strands 105, 106, is displaced from the centrepoint 117 by a centre distance 109, 110, such that the location of theapex point 107, 108 is different from the centre point 117.

The centre distance 109, 110, between the apex 107, 108, and the centrepoint may vary, and is preferably less than half the diameter (A) of thedevice 100, or less than half the cross-section at the location of theapex point in case the device 100 is non-circular.

By having a displacement of at least one of the loop strands 105, 106,from the centre point 117 the device 100 may exhibit a smallercross-section or diameter in the collapsed state of the device 100, asless strands are present at the tip or centre point 117 of the device.At the same time by having the apex point 107, 108, at a distance fromthe periphery 113 of the distal end 102 stability of the device 100 ismaintained. I.e. a partly closed distal end 102 is obtained even if nocentre strands 115 extend across the centre point 117, as shown in FIG.4. Having a partly closed distal end 102, i.e. where the apex points107, 108, of the loop strands are positioned between the centre 105 andthe periphery 113 of the distal end 102, may also facilitate occlusionby allowing for easier fixing of a membrane (not shown) in the braiding101 of the distal end 102 due to a part of the braiding 101 of thedistal portion 102 extending in the radial direction. The braiding 101extending in the radial direction at the distal end 102 may also improvethe occlusion ability itself without the need for additional elements.As shown in FIGS. 2-6, 8, the apex points 107, 108, may be displacedfrom the centre 105 by different distances. The flexibility of thedevice 101 may thereby be improved while maintaining structuralrigidity.

If the device 100 is stretched substantially along a longitudinal axis502 passing through the centre point 117, see FIG. 8, the centre point117 will correspond substantially to the tip of the device 100.

The device 100, 200, 300, 400, 500, 600, is preferably collapsed bystretching. The device 100, 200, 300, 400, 500, 600, may also becollapsed by compression. Hence, as the loop strands 105, 106, andfurther loop strands 206, 306, according to embodiments in FIG. 3, andFIG. 8, are displaced from the centre point 117 less strands will bepresent at the tip 801 which may reduce the cross-section of the tip801.

The apex point 107, 108, 208, 308, of each of the loop strands may bedisplaced from the centre point 117 along a longitudinal axis 502 whenthe device is in the collapsed state. The centre point 117 maycorrespond to a distal tip 802 when the device 100, 200, 300, 400, 500,600, is in the collapsed state, as shown in FIG. 8.

The braiding of the distal end 102 may comprise a distal surface 116 ofthe at least one thread. The distal surface 116 extends from the apexpoint 107, 108, 208, 308, of each of said loop strands to the centrepoint 117. The distal surface 116 may comprise the loop strands 105,106, 206, 306, or centre strands 115. In case the device 100, 200, 300,400, 500, 600, is in the collapsed state the distal surface 116 mayextend from the apex point 107, 108, 208, 308, of each of said loopstrands to the distal tip 802 of the device, as shown in FIG. 8. Hence,the braiding 101 in which the apex points 107, 108, 208, 308, isconfined, may be continuous from these apex points to the centre point117. As shown in FIG. 4 the distal end 102 of the device 400 may also beopen. The centre strands 115 improves the stability of the device,and/or occlusion effectiveness, while the flexibility and smallcross-section is maintained in the collapsed state due to the loopstrands being displaced from the centre point 117.

By having a plurality of loop strands displaced from the centre point117 by a plurality of centre distances 109, 110, and furtherdisplacement by centre distances 206, 306, according to embodiments inFIG. 3, and FIG. 8, a larger portion of the distal end 102 may exhibit asmaller cross-section in the collapsed state of the device 100. Further,the cross-section of the entire device 100 may be reduced by thedisplacement. FIG. 8 may be illustrative of a device 100 in both thecollapsed state and in the expanded state. Hence, the cross-section maybe reduced in the expanded state as well. By provision of a smallercross-section the device 100 in the collapsed state the device 100 maybe delivered to a target site in a patient through a delivery devicewith a reduced cross-section, which may lead to an easier deliveryprocedure or manipulation of the delivery device in the patient.

Further thanks to the displacement of the loop strands 105, 106, 206,306, from the centre point 117 the amount of force required to compressthe device from the expanded state, as illustrated in FIG. 1-4, to thecollapsed state, as illustrated in FIG. 8, is reduced. This is thanks tothe fact that the loop strands 105, 106, 206, 306, do not cross thecentre point 117. Thus, the amount of threads that must be bent at thecentre point 117 when compressing the device 100 is reduced. Each threadcrossing the centre point 117 or a region close to the centre point 117that is subjected to substantial deformation when compressing the device100 to the collapsed state has a certain amount of structural integrityand an associated force that must be exceeded in order to deform thethread. By having several loop strands 105, 106, 206, 306 displaced fromthe region subjected to the most of the deformation, e.g. the centrepoint 117 or tip 801, the force required for deformation is thussubstantially reduced. A more flexible braided device 100-600 is thusobtained, which for example can be more easily retracted into a cathetersheath and which exerts less frictional force on the walls of thecatheter thereby increasing the ease of operation of the device 100-600in the catheter, for example during push and pull motion.

In FIG. 1 the device 100 comprises a group 111 of a plurality of loopstrands 105, 106, that are displaced from the centre point 117 such thatthe apex points 107, 108, of the group 111 lie on an imaginary circle112 enclosing the centre point 117. The apex points 107, 108 also lie ata distance from a periphery 113 of the distal end 102.

The stability of the device is thereby improved as compared to the casewhen the wires turn at the periphery of the braiding, as with the distalend of a device of a tubular braiding. It is also easier to manufacturethe device according to the invention compared to such tubularbraidings. As illustrated in FIGS. 1-4 the distance the apex points liesfrom the periphery 113 may vary from less than half of the radius, e.g.at a fourth of the radius, to more than half the radius, e.g. threefourths of the radius. Similarly, FIG. 2-4 shown devices 200-400comprising at least one group 111, 211, 311 of a plurality of loopstrands 105, 106, 206, 306, that are displaced from the centre point 117such that the apex points 107, 108, 208, 308, of the at least one grouplie on at least one imaginary circle 112, 212, 312 enclosing the centrepoint 117. The apex points 107, 108, 208, 308, also lie at a distancefrom a periphery 113 of the distal end 102. The radius of the at leastone imaginary circle 112, 212, 312 corresponds to the centre distances109, 110, 210, 310. An increased radius may provide a more flexibledevice 100-400 with less force required for compression of the device100-400 from its expanded state to its collapsed state.

The at least one imaginary circle 112, 212, 312 may have its circlecentre 114 corresponding to the location of the centre point 117.Thereby, the at least one group 111, 211, 311 of the plurality of loopstrands 105, 106, 206, 306, are displaced concentrically from the centrepoint 117. Alternatively, the device 100-400 may have an asymmetricalposition of the at least one imaginary circle 112, 212, 312 with respectto the centre point 117. Optionally, imaginary circles 112, 212, 312 maybe equidistantly distributed from each other in radial direction of thedistal end 102.

In FIG. 2 the loop strands 106, 206, comprise two groups 111, 211, ofpluralities of loop strands. The first group 111 and the second group211 of the plurality of loop strands have a first and second pluralityof apex points 108, 208, respectively. The first and second plurality ofloop strands are displaced from the centre point 117 such that the firstplurality of apex points 108 lies on the periphery of an imaginarycircle 112 having a first radius 110 and the second plurality of apexpoints 208 lies on the periphery of an imaginary circle 212 having asecond radius 210 which different from the first radius 110. The firstand second radius 110, 210, are less than the diameter (A) of the distalend 102.

In FIG. 3 a third group 311 of the plurality of loop strands has a thirdplurality of apex points 308 that lies on the periphery of an imaginarycircle 312 having a third radius 310 different from the first and secondradius 110, 210.

The first, second, and third groups 111, 211, 311, of the plurality ofapex points 108, 208, 308, may lie concentrically with respect to thecentre point 117.

Each group 111, 211, 311, of the pluralities of loop strands may beformed by a plurality of threads respectively, or by a single thread.The braiding may 101 comprise any number of threads.

The distal end 102 may be closed, as shown in FIG. 1-3, preferably by aplurality of centre stands 115 of the braiding 102 crossing each otherat the centre point 117. The distal end 102 may also be open, as shownin FIG. 4. An open distal end 102 may be advantageous in someapplications.

The amount of the centre strands 115 may be varied. The flexibility ofthe device 100-600 may be adjusted by varying the amount of centrestrands 115, hence providing customization of the device 100-600 tovarious applications. Fewer centre strands 115 may decrease the forcerequired for compressing the device 100-600 from the expanded state tothe collapsed state, hence increasing the flexibility. The ratio betweenthe amount of the centre strands 115 and the loop strands may be set toa defined value. In FIG. 1 and FIG. 2 50% of the threads are loopedback, i.e. are comprised of loop strands 105, 106, 206, 306. In FIG. 275% of the threads are looped back, and in FIG. 4 100% of the threadsare looped back. By varying the amount of loop strands the flow throughthe device may also be optimized. More or less dense loop strands ormore strands crossing the centre may increase the maximum flowthroughput of the device.

The device may comprise biocompatible fibres or patches of for exampleof PET that support sealing of the blood flow through the device.

Each of the apex points 107, 108, 208, 308 may be equally spaced apartaround the peripheries of the at least one imaginary circle 112, 212,312.

The distal end 102 may have any shape such as a circular disc shape,and/or spherical shape, and/or elongate shape.

FIG. 5a shows a perspective view of a device 500 having a braiding 101according to the embodiment in FIG. 3. FIG. 5b show a side view of thedevice 500 in FIG. 5a according to an embodiment. FIGS. 5a-b mayrepresent a PFO occluder with two double layer discs. The braiding 101of the device 500 may comprise loop strands according to any of thedevices 100-400, e.g. one, two, or more groups of loop strands beingdisplaced from the centre point 117 at different distances.

As shown in FIGS. 5a-b , a longitudinal axis 502 extends between centrepoints of the distal and proximal ends the device 500. The occlusiondevice 500 has rotational symmetry around the longitudinal axis 502, andthe centre point 117 coincide with the intersection of the longitudinalaxis 502 with the distal end 102 of the device 500, which may also bethe case for the devices 100-400.

FIG. 6a shows a perspective view of a device 600 having a braiding 101according to the embodiment in FIG. 3. FIG. 6b show a side view of thedevice 600 in FIG. 6a according to an embodiment. FIGS. 6a-b mayrepresent an ASD occluder with two double layer discs. The braiding 101of the device 600 may comprise loop strands according to any of thedevices 100-400.

FIGS. 7a-b and FIG. 9 illustrates a method 900 of manufacturing amedical implantable occlusion device 100-400 of a braiding 101 of atleast one thread. The method 900 comprises forming 901 loops by loopstrands 106, 206, 306 of the at least one thread by an annular braidingtool 701 having a centre point 702. Each loop strand 106, 206, 306 has acurved shape and extends away from the centre point 702 of the braidingtool 701. The apex point 108, 208, 308, of each of the loop strands 106,206, 306, corresponds to the turning point of the curved shape and tothe point of each of the loop strands 106, 206, 306, being arrangedclosest to said centre point 702. At least one of the loop strands 106,206, 306, is displaced from the centre point 702 by a centre distance110, 210, 310, such that the location of the apex point 108, 208, 308,is different from the centre point 702. As is shown in FIG. 7a-b theapex points 108, 208, 308, lie at a distance from the peripheral edge ofthe braiding tool 701. A partially closed braiding 101, as discussedabove, with returning loops may thereby be manufactured with improvedstability over a mere tubular braiding, while maintaining flexibility.An improved occlusion ability is also provided, e.g. by the braiding 101extending in the radial direction of the distal end 102, or by easierincorporation of a membrane (not shown) in the braiding. As shown inFIG. 7a-b the apex points 108, 208, 308, lie at different distances fromthe periphery of the braiding tool 701 or from the centre point 702. Abraiding 101 with the loop strands displaced from the centre 105 of thebraiding 101 by different distances may thereby be manufactured. Adevice 100, 200, 300, 400, 500, 600, having such braiding 101 has theadvantages as described above.

The method 900 comprises forming 902 at least one group 111, 211, 311,of a plurality of loop strands being displaced from the centre point 702such that the apex points 108, 208, 308, of the at least one group lieon at least one imaginary circle 112, 212, 312, enclosing the centrepoint 702.

The loops may be formed without crossing the loop strands 106, 206, 306,with each other.

The method 900 may comprise forming 903 a closed end of the braiding bycrossing 904 the centre point 702 with a plurality of centre strands115.

The present invention has been described above with reference tospecific embodiments. However, other embodiments than the abovedescribed are equally possible within the scope of the invention asdefined by the appended patent claims. The different features and stepsof the invention may be combined in other combinations than thosedescribed. The scope of the invention is only limited by the appendedpatent claims.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used.

The invention claimed is:
 1. A medical implantable occlusion devicehaving a collapsed state and an expanded state and comprising a braidingof at least one thread, a distal end comprised of said braiding, whereinsaid distal end comprises loops formed by loop strands of said at leastone thread and centre strands, wherein, at least in said expanded state,each loop strand having a curved shape with an apex located between aperiphery of the distal end and a centre of said distal end, and whereinat least some of said centre strands are located closer to the centre ofsaid distal end than said apex of said loop strands.
 2. The occlusiondevice according to claim 1, wherein at least one of said loop strandsis displaced from said centre point by a centre distance such that thelocation of said apex is different from said centre point, and whereinsaid apices lie at a distance from the periphery of said distal end sothat said distal end between the apex and the centre is closed by aplurality of centre stands.
 3. The occlusion device according to claim1, wherein at least some of said centre stands are crossing each otherat said centre.
 4. The occlusion device according to claim 3, wherein atleast some of said of centre stands are crossing each other at a regionclose to said centre.
 5. The occlusion device according to claim 3,wherein at least some of said of centre stands are crossing said centre.6. Occlusion device according to claim 1, wherein at least one group ofa plurality of loop strands are displaced from said centre such thatsaid apex of each loop strand of said at least one group lie on at leastone imaginary circle enclosing said centre.
 7. Occlusion deviceaccording to claim 6, wherein said at least one imaginary circle has acircle centre corresponding to the location of said centre of saiddistal end, whereby said apex of each loop strand of said at least onegroup are displaced concentrically from said centre.
 8. Occlusion deviceaccording to claim 6, wherein said at least one imaginary circle has acircle centre corresponding to the location of said centre of saiddistal end, whereby said apex of each loop strand of said at least onegroup are displaced concentrically from said centre and equidistantlydistributed from each other in a radial direction of said distal end. 9.Occlusion device according to claim 1, wherein said loop strandscomprise at least two groups of pluralities of loop strands, wherein afirst group of said plurality of loop strands has a first group ofplurality of apices and a second group of said plurality of loop strandshas a second group of plurality of apices, wherein said apices of saidfirst group of plurality of apices forms an imaginary circle having afirst radius, and said apices of said second group of plurality ofapices forms an imaginary circle having a second radius, said firstradius being different than said second radius and said first radius andsaid second radius being less than a radius of said periphery of saiddistal end.
 10. Occlusion device according to claim 9, wherein a thirdgroup of said plurality of loop strands has a third plurality of apicesforming a third imaginary circle having a third radius being differentfrom said first radius and said second radius.
 11. Occlusion deviceaccording to claim 10, wherein said first group, said second group, andsaid third group of said plurality apices are formed concentrically withrespect to said centre of said distal end.
 12. Occlusion deviceaccording to claim 9, wherein each group of said plurality of loopstrands are formed by a plurality of threads.
 13. Occlusion deviceaccording to claim 1, wherein a plurality of loop strands are displacedfrom said centre of said distal end by a plurality of centre distances.14. Occlusion device according to any claim 1, wherein said distal endhas a circular disc shape, and/or a spherical shape, and/or an elongateshape.
 15. Occlusion device according to claim 1, wherein the ratiobetween the number of centre strands relative to the number of loopstrands is set to a defined value.
 16. Occlusion device according toclaim 1, wherein a plurality of apices of said loop strands are spacedapart and form at least one imaginary circle.
 17. Occlusion deviceaccording to claim 1, comprising a proximal end and a longitudinal axisextending through said occlusion device between centre points of saiddistal and proximal ends, wherein said occlusion device has rotationalsymmetry around said longitudinal axis, and wherein said centre of saiddistal end coincides with said longitudinal axis, and wherein said apexof each of said loop strand is displaced from longitudinal axis whensaid device is in said collapsed state.
 18. Occlusion device accordingto claim 1, wherein said braiding of said distal end comprises a centraldistal surface of said at least one thread extending from said apex ofeach of said loop strands and at least partially towards said centre ofsaid distal end, wherein said central distal surface is formed at leastpartially by said centre strands.
 19. A medical implantable occlusiondevice having a collapsed state and an expanded state and comprising abraiding of at least one thread, a distal end comprised of saidbraiding, wherein said distal end comprises loops formed by loop strandsof said at least one thread and centre strands, wherein, at least insaid expanded state, each loop strand having a curved shape with an apexlocated between a periphery of the distal end and a centre of saiddistal end, and wherein said braiding of said distal end comprises acentral distal surface formed by at least one centre strand andextending at least partially between said apex of each of said loopstrands and at least partially towards said centre of said distal end.20. The occlusion device according to claim 19, wherein at least some ofsaid of centre stands are crossing each other at said centre.
 21. Theocclusion device according to claim 20, wherein at least some of said ofcentre stands are crossing each other at a region close to said centrebut are not crossing said centre.
 22. The occlusion device according toclaim 20, wherein at least some of said centre stands are crossing saidcentre.
 23. Occlusion device according to claim 19, wherein at least onegroup of a plurality of loop strands are displaced from said centre suchthat said apex of each loop strand of said at least one group form atleast one imaginary circle enclosing said centre.
 24. Occlusion deviceaccording to claim 23, wherein said at least one imaginary circle has acircle centre corresponding to the location of said centre of saiddistal end, whereby said apex of each loop strand of said at least onegroup are displaced concentrically from said centre.
 25. A medicalimplantable occlusion device having a collapsed state and an expandedstate and comprising a braiding of at least one thread, a distal endcomprised of said braiding and having a first portion and a secondportion, wherein said distal end comprises loops formed by loop strandsof said at least one thread and centre strands, wherein, at least insaid expanded state, at least one loop strand having a curved shape withan apex located between a periphery of the distal end and a centre ofsaid distal end, and at least one centre strand located closer to thecentre than the apex of said at least one loop strand, wherein saidsecond portion is located closer to a centre of the distal end than saidfirst portion, said first portion is formed by said at least one loopstrand in combination with said least one centre strand, and said secondportion is formed by said least one centre strand but not by said atleast one loop strand.
 26. The occlusion device according to claim 19,wherein at least some of said centre stands are crossing each other atsaid centre.
 27. The occlusion device according to claim 26, wherein atleast some of said of centre stands are crossing each other at a regionclose to said centre but are not crossing said centre.
 28. The occlusiondevice according to claim 20, wherein at least some of said of centrestands are crossing said centre.
 29. Occlusion device according to claim25, wherein at least one group of a plurality of loop strands aredisplaced from said centre such that said apex of each loop strand ofsaid at least one group form at least one imaginary circle enclosingsaid centre.
 30. Occlusion device according to claim 29, wherein said atleast one imaginary circle has a circle centre corresponding to thelocation of said centre of said distal end, whereby said apex of eachloop strand of said at least one group are displaced concentrically fromsaid centre.